*,
::before,
::after {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

body {
  background-color: black;
  font-family: Arial, Helvetica, sans-serif;
  display: flex;
  justify-content: center;
  padding-top: 4rem;
}

.calculator {
  width: 350px;
  height: 500px;
}

h1 {
  color: white;
  text-align: center;
  padding-bottom: 5rem;
  font-size: 3em;
}

.display {
  color: black;
  height: 50px;
  padding-bottom: 4rem;
  padding-right: 2rem;
  text-align: right;
  width: 100%;
  background-color: black;
  border: transparent;
  color: white;
  font-size: 3rem;
  outline: transparent;
  text-overflow: ellipsis;
  overflow: hidden;
  white-space: nowrap;
}

.keys {
  width: 100%;
  height: 450px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(5, 1fr);
  gap: 5px;
}

button {
  font-size: 1.5rem;
  font-weight: 500;
  background-color: #313131;
  color: white;
  border: none;
  width: 80px;
  height: 80px;
  border-radius: 40px;
  transition: .4s ease;
  cursor: pointer;
}

.yellowish {
  background-color: #f69a06;
  font-size: 2.5rem;
}

#special {
  padding-top: 20px;
}

.grayish {
  background-color: #a0a0a0;
}

.span {
  width: 100%;
  grid-area: 5 / 1 / 6 / 3;
  display: flex;
  align-items: center;
  padding-left: 35px;
}

button:hover {
  opacity: 0.6;
}


.is-depressed {
  opacity: 0.5;
}